Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
Q: Quantenoptik
Q 17: Poster: Cooling and Trapping
Q 17.37: Poster
Mittwoch, 4. April 2001, 12:30–15:00, AT2
Vortex nucleation and shape deformations in rotating Bose-Einstein condensates — •Meret Krämer, Francesca Zambelli, Lev Pitaevskii, and Sandro Stringari — Dipartimento di Fisica, Università di Trento and Istituto Nazionale per la Fisica della Materia, I-38050 Povo-Trento, Italy
We study the total energy of a rotating Bose-Einstein condensate in the presence of a single-quantized straight vortex line and a shape deforming irrotational flow. We analyze the dependence of the energy on the condensate deformation and on the displacement of the vortex from the center. At a frequency Ωc a central vortex in a non-deformed condensate becomes the groundstate of the system. However, shape deformations are found to be crucial for the nucleation of a vortex. For a non-deformed condensate, the initial vortexless state and the central vortex state are separated by an energy barrier and the nucleation is not possible. We show that the system can bypass this barrier by taking a quadrupole deformation only at a critical frequency Ωc larger than Ωc. We find a strong dependence of Ωc on the particle number and on the static deformation of the trap. The recent experiments carried out at the ENS on the nucleation of vortices are analyzed.